The primary objective of this proposal is to purchase an ex vivo specimen microcomputed tomography (ex vivo microCT) instrument. We are proposing the purchase of a SkyScan 1172 microCT system, which will serve 11 federally funded investigators (10 NIH, 1 Department of Energy (DOE)) in 16 federally funded research projects (14 NIH, 1 NIOSH, 1 DOE) at Temple University. Our university lacks any type of microCT system, although our need is large and continues to grow. The instrument in the proposed application will allow excellent resolution of fine structure even in low contrast samples, so that new applications for microCT can be accommodated. The SkyScan 1172 can image specimens with high-resolution - less than 1 5m voxel size and low-contrast resolution of 5 5m. A typical scan takes 30 min to 1 hr, and the system comes with a reconstruction workstation of clustered PCs and special software to rapidly calculate information from each image slide, so that a user can reconstruct a scan while the next specimen is scanning. This will provide the high throughput required to service the needs of our research community for microCT. The digital data then permits quantitative determination of a variety of structural parameters in bone, cartilage, muscle, fat, vasculature and tumors. This high-resolution microCT instrument will be housed at our Health Science campus in the Imaging Center. The addition of microCT will significantly enhance the available imaging services and will complement the light-based, fluorescence technologies that already exist in this center. The instrument will be administered by a committee of faculty members drawn from the users from the Schools/Colleges of Medicine, Dentistry, Engineering, Health Professions, and Science and Technology. Applications for the proposed high-resolution microCT SkyScan 1172 instrument include: 1) Imaging and quantification of bone degenerative changes induced by performing repetitive and forceful work tasks, and the effectiveness of interventions. 2) Imaging and quantification of bone architecture in studies of genetically engineered mice (transgenic and knockout models), pathological bone remodeling (such as after ovariectomy and low calcium diet), and after head trauma fracture. 3) Detection of the earliest stages of dental caries and the development of preventative and treatment interventions. 4) Examination of mechanical properties of synthetic dental composites with the goal of improving dental restorative materials. 5) To study vascular formation and atherosclerosis in, and contributing factors of, stroke and cardiovascular disease. 6) To assess effectiveness of therapeutic approaches for liver and lung diseases and cancer. The acquisition of the SkyScan 1172 is essential for continued progress of these and future projects requiring this state-of-the-art technology.